samples: lwm2m: v1.1 w/a TLV enabled bootstrap

With the LwM2M v1.1 the preferred content format would be SenML CBOR but
the current implementation doesn't tell it to a bootstrap server. In
those cases bootstrap uses TLV so there is need to enable it separately.
Usage of TLV is discouraged with v1.1. This w/a can be removed once
sending preferred content format functionality is implemented.

Signed-off-by: Veijo Pesonen <veijo.pesonen@nordicsemi.no>

Author: Veijo Pesonen

samples/nrf9160/lwm2m_client/overlay-avsystem-bootstrap.conf

@@ -1,3 +1,6 @@
 CONFIG_LWM2M_RD_CLIENT_SUPPORT_BOOTSTRAP=y
 CONFIG_LWM2M_CLIENT_UTILS_SERVER="coaps://eu.iot.avsystem.cloud:5694"
 CONFIG_LWM2M_SECURITY_INSTANCE_COUNT=3
+
+# V1.1 w/a until we give SeNML CBOR as the preferred content format
+CONFIG_LWM2M_RW_OMA_TLV_SUPPORT=y

samples/nrf9160/lwm2m_client/overlay-leshan-bootstrap.conf

@@ -1,2 +1,5 @@
 CONFIG_LWM2M_RD_CLIENT_SUPPORT_BOOTSTRAP=y
 CONFIG_LWM2M_CLIENT_UTILS_SERVER="coaps://leshan.eclipseprojects.io:5784"
+
+# V1.1 w/a until we give SeNML CBOR as the preferred content format
+CONFIG_LWM2M_RW_OMA_TLV_SUPPORT=y